How to Zoom in:

1. Double click on the image to zoom in to that point.
2. Or hold down the  key (mac) or the ctrl key (PC) and click on the image.
3. Or hold down the plus key to increment the zoom.
4. Or hold down the  key (mac) or the ctrl key (PC) and use the mouse wheel (not in Firefox).

How to Zoom out:

1. Double click on the zoomed image to zoom out.
2. Or hold down the  + alt key (mac) or the ctrl + alt key (PC) and click on the image.
3. Or hold down minus key to decrement the zoom.
4. Or hold down the  key (mac) or the ctrl key (PC) and use the mouse wheel (not in Firefox).